The chemical isolation of tin from alloys containing titanium, antimony, vanadium and other elements can be accomplished (A. M. Leblond, R. Boulin, Dosage de l'étain dans les métaux ferreux, Méthode spectrophotométrique á la phénylfluorone, Chim. analyt., 50, 171-177 (1968)). The method consists of sample dissolution in the mixture of solutions of perchloric (HClO4) and sulfuric (H2SO4) acid, extraction of tin with benzene followed by re-extraction of tin with diluted solution of H2SO4. Since the method is only applied for spectrophotometric determination of tin, it does not provide high chemical purity tin, especially radioactive tin in NCA form (NCA radiotin) which must be separated from macroamounts of antimony and titanium as well as from radionuclides of tellurium, indium, vanadium and scandium generated under irradiation of TiSb with accelerated charged particles.
One method for the chemical recovery of NCA radiotin is based on the procedure of processing the targets containing natural or enriched metallic antimony (L. F. Mausner et al., Nuclear data for production of Sn-117m for biomedical application, J. Radiation Effects, 94, 50-63 (1986)). The method includes dissolution of antimony irradiated with accelerated charged particles followed by precipitation of tellurium using sulfur dioxide and chromatographic isolation of NCA radiotin using an anion exchange resin and solutions of hydrochloric (HCl) and HClO4. However, the method does not provide purification of radiotin from titanium, so it does not allow titanium-containing materials to be processed. Another disadvantage of the method is low level of radionuclidic purity, because the radiochemical procedure of radiotin recovery is elaborated for cross section measurements rather than for medical applications.
Another method for the chemical recovery of NCA radiotin deals with the irradiated targets of metallic antimony in the form of a massive monolith sample in a hermetic shell (B. L. Zhuikov et al., Process and targets for production of no-carrier-added radiotin, RF Patent No. 2313838 (2007)). The radiochemical procedure comprises dissolution of irradiated antimony followed by extraction of antimony with dibutyl ether and chromatographic purification of radiotin on silica gel from isotopes of tellurium and indium as well as from the traces of antimony. However, the method is only developed for processing metallic antimony which has low heat conductivity and melting point as well as high vapor pressure. As a result, maximal current of accelerated charged particles is restricted to a certain low value depending on target thickness, material of the shell, efficiency of the cooling system and beam geometry.
Producing NCA radiotin may be more effective if more temperature resistant material such as intermetallide TiSb is used instead of antimony (J. L. Murray, Binary Alloy Phase Diagrams, Second Edition, Ed. T. B. Massalski, ASM International, Materials Park, Ohio, 3, 3311-3312 (1990); H. Nowotny, J. Pesl, Untersuchungen im system Titan-antimon, Monatshefte fuer Chemie, 82, 336-343 (1951)). Thus, the development of procedure for chemical recovery of radiotin from irradiated TiSb is desirable.